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T Chandra

Publications and source records attributed to T Chandra.

53 records · Page 3Linked to original sources
PubMed1981

Hormonally regulated mammalian gene expression: steady-state level and nucleotide sequence of rabbit uteroglobin mRNA.

Uteroglobin is a protein that is synthesized in large quantities by the rabbit uterine endometrial cells and secreted into the uterine lumen around the time of implantation of the developing blastocysts. The protein is also synthesized constitutively at a low level in the lung. In the uterus, synthesis of the protein is induced by progesterone but repressed by estradiol; whereas in the lung, it is not hormonally responsive. Using a full-length cDNA clone, we have established the nucleotide sequence of uteroglobin mRNA and have determined its levels in uterus and lung during early pregnancy. The clone, pUG617, contains all but 24 nucleotides at the 5' untranslated region of the structural gene. To establish the full mRNA sequence, we isolated a 5' end-labeled DNA fragment from pUG617 and extended its length using reverse transcriptase after hybridization with uterine poly(A)-containing RNA. The 5'-terminal sequence of uteroglobin mRNA was established by sequencing the extended DNA fragment. The nucleotide sequence of the peptide-coding portion of the gene has resolved some previously reported discrepancies in the amino acid sequence of the mature protein and those in the signal peptide. By comparison of sequences with a partial uteroglobin cDNA clone isolated by another laboratory, a polymorphic nucleotide at position 246 of the gene has been identified, where a G-A transition has caused an amino acid substitution from aspartic acid to asparagine at residue 46 of the mature protein. Analysis of steady-state RNA levels in the uterus has shown that the induction and repression of uteroglobin synthesis during early pregnancy is the result of accumulation and depletion of its mRNA, respectively. During the same period in the lung, no consistent changes in uteroglobin mRNA level were evident, reflecting the constitutive levels of the protein in this tissue.

Amino Acid Sequence↗
PubMed1980

Cloning and analysis of a cDNA coding for bovine prothrombin.

Poly(A)-RNA enriched for prothrombin was isolated by specific immunoprecipitation of bovine liver polysomes. Prothrombin consisted of about 8% of the cell-free translation products of this RNA. A double-stranded cDNA was synthesized by using reverse transcriptase (RNA-dependent DNA nucleotidyltransferase) and made blunt-ended with nuclease S1. After tailing with dCTP and terminal transferase, the double-stranded cDNA was annealed to pBR322 DNA that had been cleaved previously at the single Pst I site and similarly tailed with dGTP. The resulting plasmids were used to transform Escherichia coli strain RR1 under P3-EK1 conditions. Sixty-three tetracycline-resistant clones were obtained that hybridized to 32P-labeled cDNA synthesized from prothrombin-enriched mRNA. Recombinants containing cDNA to prothrombin mRNA sequences were screened by a solution hybridization assay with a [3H]cDNA synthesized from mRNA. This enriched mRNA was 50% prothrombin mRNA, as determined by a reticulocyte lysate translation assay. Three positive clones were identified by this assay; they contained bovine DNA inserts of 700, 500, and 400 base pairs. The DNA sequence of the 700-base-pair insert was then determined. This recombinant plasmid contained DNA coding for the carboxyl-terminal 160 residues of bovine prothrombin followed by a noncoding region of 119 base pairs and a poly(A) tail of 60 base pairs.

Amino Acid Sequence↗
PubMed1977

Role of thyroid gland on the peroxidase and iodinating enzymes of submaxillary gland.

The peroxidase (EC 1.11.1.7) and iodinase (EC 1.11.1.8) activities of rat submaxillary gland were found to be increased after thyroidectomy. The enzyme activities were maximal on the seventh day after operation and then decreased slightly. However, the enzyme activities were still more than 100% even 28 days following operation. Administration of thyroxine (10mug/100 g body weight) prevented the increase. Puromycin, cycloheximide, and actinomycin D, the inhibitors of protein synthesis, as well as thiouracil partially abolished the increase of activities. These results suggest that thyroxine acts as a regulator of the iodinase and peroxidase enzyme(s) of submaxillary gland,

Animals↗
PubMed1976

Protein kinases of the chick oviduct: a study of the cytoplasmic and nuclear enzymes.

Subcellular fractionation of oviduct tissue from estrogen-treated chicks indicated that the bulk of the protein kinase activity of this tissue is located in the cytoplasmic and nuclear fractions, DEAE-cellulose chromatography of cytosol revealed a major peak of cAMP stimulatable activity eluting at 0.2 M KCl. This peak was further characterized and found to exhibit properties consistent with cytoplasmic cAMP dependent protein kinases isolated from other tissues; it had a Km for ATP of 2 X 10(-5) M, preferred basic proteins such as histones, as substrate, and had a M of 165 000. Addition of 10(-6) M cAMP caused the holoenzyme to dissociate into cAMP binding regulatory subunit and a protein kinase catalytic subunit. Extraction of purified oviduct nuclei with 0.3 M KCl released greater than 80% of the kinase activity in this fraction. Upon elution from phospho-cellulose, the nuclear extract was resolved into two equal peaks of kinase activity (designated I and II). Peak I had a sedimentation coefficient of 3S and a Km for ATP of 13 muM. while peak II had a sedimentation coefficient of 6S and a Km for ATP of 9 muM. Both enzymes preferred alpha-casein as a substrate over phosvitin or whole histone, although they exhibited different salt-activity profiles. The cytoplasmic and nuclear enzymes were well separated on phospho-cellulose and this resin was used to quantitate the amount of cAMP dependent histone kinase activity in the nucleus and the amount of casein kinase activity in the cytosol. Protein kinase activity in nuclei from estrogen-stimulated chicks was found to be 40% greater than hormone-withdrawn animals. This increase in activity was not due to translocation of the cytoplasmic protein kinase in response to hormone, but to an increase in nuclear (casein) kinase activity. During the course of this work, we observed small but significant amounts of cAMP binding activity very tightly bound to the nuclear fraction. Solubilization of the binding activity by sonication in high salt allowed comparison studies to be performed which indicated that the nuclear binding protein is identical with the cytoplasmic cAMP binding regulatory subunit. The possible role of the nuclear binding activity is discussed.

Animals↗
PubMed1976

DNA-cellulose column chromatography of phosphorylated nucleolar nonhistone proteins.

A salt-extraction procedure was used to isolate a nucleolar nonhistone protein fraction, containing [32P]phosphoserine, from the nucleoli of Novikoff hepatoma ascites cells. These proteins are similar in amino-acid composition to whole nuclear (chromosomal) nonhistone proteins. DNA-cellulose column chromatography showed that this fraction contains DNA-binding phosphoproteins, some of which will bind only to homologous (Novikoff) nucleolar or nuclear DNA.

Amino Acids↗
PubMed1967

Toxicity of different diets contaminated with various fungi to rice moth larvae (Corcyra cephalonica st).

Growth studies of rice moth larvae (Corcyra cephalonica st) have been carried out in groundnut meal and wheat bran contaminated with A. flavus, A. oryzae, P. purpurogenus and P. rubrum. It was observed that the diets contaminated with A. flavus only are toxic to these larvae. Wheat bran contaminated with A. flavus is more toxic than contaminated groundnut meal. The higher toxicity of wheat bran contaminated diet has been discussed. Aflatoxins produced in different substrata are shown to differ when analysed chromatographically. Growth studies of rice moth larvae have also been carried out with aflatoxin and the susceptibility of these larvae has been established.

Aflatoxins↗
PubMedDate not supplied

Biochemical modes of action of Cassia occidentalis and Cardiospermum halicacabum in inflammation.

The anti-inflammatory activity of Cassia occidentalis leaf powder and an ethanol extract of Cardiospermum halicacabum aerial parts were assayed in male albino rats using carrageenan-induced rat paw edema. C. occidentalis was maximally active at a dose of 2000 mg/kg, while the C. halicacabum extract was maximally effective at a dose of 500 mg/kg. In the cotton pellet granuloma assay, these drugs were able to suppress the transudative, exudative and proliferative components of chronic inflammation. Further, these drugs were able to lower the lipid peroxide content and gamma-glutamyl transpeptidase and phospholipase A2 activity in the exudate of cotton pellet granuloma. The increased alkaline phosphatase activity and decreased A/G ratio of plasma in cotton pellet granulomatous rats were normalized after treatment with these drugs. C. occidentalis powder and C. halicacabum extract were able to stabilize the human erythrocyte membrane against hypotonicity-induced lysis. It is likely that these drugs may exert their anti-inflammatory activity by inhibition of phospholipase A2, resulting in the reduced availability of arachidonic acid, a precursor of prostaglandin biosynthesis, and/or by stabilization of the lysosomal membrane system.

Animals↗
PubMedDate not supplied

Cloned human phenylalanine hydroxylase gene allows prenatal diagnosis and carrier detection of classical phenylketonuria.

The human gene for the hepatic enzyme phenylalanine hydroxylase has been cloned and used to analyse the phenylalanine hydroxylase locus in the human genome. The detection of polymorphisms in this locus by several restriction enzymes has allowed feasibility studies of prenatal diagnosis of classical phenylketonuria and identification of carriers of the trait. Results indicate that these services could be provided for up to 75% of all families with phenylketonuric children in the general Caucasian population.

Alleles↗
PubMedDate not supplied

Predictive value of fine needle aspiration cytology of bone lesions.

OBJECTIVE: To determine the predictive value of fine needle aspiration cytology (FNAC) of bone lesions. STUDY DESIGN: The study consisted of data retrieval on 200 cases of bone lesions and their cytohistopathologic correlation to assess the diagnostic efficacy of FNAC in these cases, considering histopathology as the gold standard. The diagnostic indices were calculated by a decision matrix comparison. RESULTS: On cytohistopathologic correlation of 200 cases, 106 (53.0%) were malignant bone tumors (MBT): 97 primary and 9 metastatic; and 76 were benign bone lesions (BBL), 58 neoplastic (29%) and 18 nonneoplastic (9%). The aspirated material was adequate in 181 cases, whereas in 18 cases cytohistopathologic examination revealed no bony lesion. Thus, there were 163 evaluable cases, of which the specific morphologic diagnoses on FNAC were possible in 141 cases (86.5%), with a solitary false positive and 8 false negatives. The percentage of inadequate aspirates was more with BBL (13.2%) than MBT (8.5%). The overall diagnostic accuracy and sensitivity of bone lesions were 95.0%, whereas specificity, positive predictive value (PPV) and negative predictive value (NPV) were 94.7%, 99.4% and 69.2%, respectively. The sensitivity of FNAC was better (95.8%) with MBT as compared to BBL (91.7%), whereas specificity and PPV were almost equal (98.8% and 99.2%) in both cases. The NPV in cases of BBL was higher (97.8%) than in MBT (95.2%). These diagnostic indices were calculated excluding the inadequate cases. CONCLUSION: High PPV and NPV indicate the reliability of FNAC for the diagnosis of bone lesions.

Adolescent↗
PubMedDate not supplied

Primary intrapulmonary teratoma presenting as pyothorax.

A female patient presented with empyema thoracis and was planned for decortication. Peroperatively a cystic mass was found in the left lower lobe which was resected and diagnosed as a case of teratoma of lung on histopathological examination. This unusual case of primary intrapulmonary teratoma is being reported here.

Adult↗